Tire pressure monitoring systems (TPMS) on vehicles are generally required in the United States, and are increasingly being implemented in Europe and Asia. Typically the TPMS sets a pressure warning threshold level which is monitored by wheel-based TPMS modules. The TPMS modules are mounted inside of each wheel, such as on the rim, valve, or in-tire, in order to periodically or continuously monitor the inflation pressure of the tire. A TPMS module typically includes a pressure sensor, a microcontroller, a power source such as a battery, and a radio frequency (RF) transmitter that communicates pressure readings from the pressure sensor to a central TPMS receiver unit mounted elsewhere in the vehicle.
The process of identifying which TPMS module sent a particular signal, and therefore which wheel may have low tire pressure, is called localization. When a low tire pressure situation is communicated to the TPMS receiver unit, it is highly desirable to know which tire is low instead of simply knowing that one of the tires has low pressure. Effective and efficient localization of TPMS modules, and therefore localization of the associated wheels, is an ongoing challenge because wheels are frequently rotated and/or changed out between summer and winter, thereby changing their positions.
In order to complete the task of assigning a location to each TPMS module, and therefore assigning a position to each associated wheel, present techniques consume long periods of time due to relying on statistically-significant sample sizes of sensor data, and/or they consume large amounts of battery power due to relying on significantly different signal strengths, high quantities of RF transmissions, long computation times, and so forth.